This proposal seeks funding to develop an integrated system for managing population and health data. The software will exploit recent advances in metadata standards, computer technology, and business information systems. The Population and Health Data Manager (PHDM) will help researchers (1) to integrate data from different periods, places, and sources, (2) to reformat complex data structures for analysis;(3) to generate simple descriptive statistics for diagnostic purposes and feasibility analyses;and (4) to export subsets of variables and cases in formats suitable for analysis in any statistical package. The system will manage population and health data of any type, including hierarchical cross-sectional microdata, longitudinal data, and small-area summary files. The technology used for retrieving and manipulating data has remained virtually unchanged since the first statistical packages were introduced almost four decades ago. As long as researchers used simple small surveys and employed only one data source at a time, the old technology worked adequately. In recent years, however, the scale and complexity of population and health data has expanded rapidly. Many sources incorporate multiple levels of hierarchy, often including a longitudinal dimension. Researchers are increasingly merging data from different sources to carry out their analyses. Moreover, the scale of available data resources is expanding at an unprecedented pace with the release of large administrative datasets and high-density census microdata samples from around the world. Reliance on antiquated data management tools imposes heavy costs on the research community. The PHDM will reduce the costs of research by allowing analysts to manipulate data without the assistance of professional programming staff. This project is directly relevant to the central mission of the NIH as the steward of medical and behavioral research for the nation: the PHDM will create tools to advance fundamental knowledge about public health and human population dynamics. These tools will advance health-related research on population growth and movement, fertility, mortality, and nuptiality, as well as the economic and social correlates of demographic behavior.